From one week to the next big headlines hit the newspapers warning of this and that healthscare associated with eating various types of food. Who are we to believe? How can we decide who is to be trusted? The answer to some extent lies in the ability of those writing about nutrition to understand the science behind it.

When digging deeper into newspaper and TV claims about nutrition or medicine, you will often find that scientific studies have been used as the source of information. Knowing what type of study has been used, can give you an insight into the accuracy of the claims being presented to you.

To assess a scientific paper's conclusions you need to understand the statistics that are used. Sometimes conclusions are wrong because the authors have misinterpreted the statistics. More commonly the study setup is wrong in the first place. Understanding the statistics used is vital for reaching a full understanding of a scientific study.

A number of hormones are used to control salt levels in the body. Aldosterone and ANP - atrial natriuretic peptide are the key players. They influence the kidneys to control sodium losses. ADH and Angiotensin II stimulate thirst to control how much water we consume to dilute salty blood.